1. Field of the Invention
The invention relates to a battery-operated electric clock, particularly a quartz-crystal clock, with a casing sealable by means of a cover and provided with a sight glass, for holding the clockwork which comprises an electric and a mechanical portion, one or more batteries, and possibly an alarm device.
2. Description of the Prior Art
Clocks are already known wherein the electrical and mechanical portion of the clockwork are contained in a two-part clockwork casing of plastic material, provided with a prolongation for holding a battery. Such a clockwork casing has two openings from which the setting elements for the hand mechanism and the alarm device project. This clockwork casing which contains the clockwork is located in a further two-part clockwork casing which consists likewise of plastic material and to the front portion of which the dial is fastened. The buzzer and the switch for switching the alarm device on and off are provided in the front portion of the clockwork casing. The rear portion of the clockwork casing has two openings for the setting elements as well as a battery opening which is sealable by means of a cover. The two portions of the clockwork casing as well as those of the clock casing are connected in such a way as to engage each other. Such clocks present the disadvantage of a voluminous and expensive structure which is difficult to manufacture.
In another known clock, the mechanical portion of the clockwork is fixed on the printed-circuit board of the electrical portion. The printed-circuit board supports a plate on the side provided with the conductor lines. The dial is mounted on the plate. On the backside of the board, holding elements for a battery are provided. The printed-circuit board is fastened, by means of four screws, in the front portion of a two-part casing. The setting elements for the hand mechanism and the alarm device are located inside the casing, so that for setting of the clock or the alarm, the rear portion of the casing must be removed. Such a clock has a structure of fewer parts and smaller volume and is easier to manufacture than the clock described above, but it has other substantial disadvantages. For instance, the electrical and mechanical portions of the clock are completely unprotected, so that while the clock or the alarm is being set, damages in the electronic parts or on the oscillating armature drive motor may occur. Since the conductor lines provided on the printed circuit board are no longer accessible after the installation of the printed circuit board in the casing, electrical testing of the individual circuits of the clock after their installation is no longer possible or is possible only under considerable difficulties. A further substantial disadvantage of this clock is that the clockwork cannot be combined with other casing shapes and types without additional structural elements.